1. Field of the Invention
This invention relates to a method and an apparatus for testing banknotes.
2. Description of Related Art
Many techniques are known for determining the denomination and authenticity of a received banknote. Banknote validating devices may be incorporated in apparatus which is capable of both receiving and dispensing banknotes, and in some cases the apparatus includes a store for banknotes to be dispensed which is replenished by received banknotes.
It is known to perform a fitness test on received banknotes to determine whether or not they are in good condition, and to prevent the dispensing of banknotes found to be in a poor condition. See WO-A-95/00932.
In order to assist the apprehension of thieves, or to deter theft, it is known to provide devices which, in certain circumstances, release ink which stains the banknotes. For example, banknotes may be transported in housings which, when opened in an unauthorised manner, automatically trigger a device which explosively releases the ink to stain the banknotes.
If such stained banknotes were introduced into banknote validators, for example housed in automatic vending machines, the banknote will either be accepted as a genuine banknote or rejected, in dependence upon the extent to which it is stained, and in dependence upon the extent to which the measurements performed upon the banknote are influenced by presence of the ink.
It would be desirable to provide a better way of handling banknotes which may have been stained.
Banknote validators tend to store large quantities of data to permit accurate recognition of multiple denominations. This data is of course dependent on the particular denominations expected to be handled by the validator. Because there is a limit to the amount of data which can be stored, it is necessary to use different validators, storing different sets of data, in areas where different denominations are expected, for example in different countries where different currencies are in use. Furthermore, because of the limited data capacity, it is sometimes not possible to arrange for the validator to recognise a sufficiently large variety of banknotes. These factors can result in customers finding unexpectedly that a validator will reject a genuine banknote, because the validator does not store data enabling recognition of that particular denomination.
It would be further desirable to provide a validator which mitigates this problem.